zebra: don't misappropriate `errno`

`errno` has its own semantics.  Sometimes it is correct to write to it.
This is not one of those cases - just use a separate `nl_errno`.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/zebra/zebra_netns_id.c b/zebra/zebra_netns_id.c
index 4cee3b89f..3da79e249 100644
--- a/zebra/zebra_netns_id.c
+++ b/zebra/zebra_netns_id.c
@@ -159,6 +159,7 @@ ns_id_t zebra_ns_id_get(const char *netnspath, int fd_param)
 	int fd = -1, sock, ret;
 	unsigned int seq;
 	ns_id_t return_nsid = NS_UNKNOWN;
+	int nl_errno;
 
 	/* netns path check */
 	if (!netnspath && fd_param == -1)
@@ -231,32 +232,31 @@ ns_id_t zebra_ns_id_get(const char *netnspath, int fd_param)
 
 			ret = -1;
 			if (err->error < 0)
-				errno = -err->error;
+				nl_errno = -err->error;
 			else
-				errno = err->error;
-			if (errno == 0) {
+				nl_errno = err->error;
+			if (nl_errno == 0) {
 				/* request NEWNSID was successfull
 				 * return EEXIST error to get GETNSID
 				 */
-				errno = EEXIST;
+				nl_errno = EEXIST;
 			}
 		} else {
 			/* other errors ignored
 			 * attempt to get nsid
 			 */
 			ret = -1;
-			errno = EEXIST;
+			nl_errno = EEXIST;
 		}
 	}
 
-	if (errno != EEXIST && ret != 0) {
-		flog_err(EC_LIB_SOCKET,
-			 "netlink( %u) recvfrom() error 2 when reading: %s", fd,
-			 safe_strerror(errno));
+	if (ret != 0 && nl_errno != EEXIST) {
+		flog_err(EC_LIB_SOCKET, "netlink( %u) recvfrom() error 2 when reading: %s", fd,
+			 safe_strerror(nl_errno));
 		close(sock);
 		if (netnspath)
 			close(fd);
-		if (errno == ENOTSUP) {
+		if (nl_errno == ENOTSUP) {
 			zlog_debug("NEWNSID locally generated");
 			return zebra_ns_id_get_fallback(netnspath);
 		}